1. Field of the Invention
The present invention relates to a method of preparing metallic magnesium(hereinafter referring to as Mg) and an apparatus for preparing the same.
More particularly, the present invention relates to a method of preparing Mg from magnesium oxide by reducing it with carbon and the apparatus therefor.
2. Description of Prior Arts
It has been known that deriving Mg from magnesium oxide by reducing it with carbon is the most effective method because the by-product of the slug is smaller than with other methods and the method is economically advantageous.
The reaction of magnesium oxide with carbon is as follows. ##EQU1##
The reaction is reversely performed at temperatures higher than 400.degree. C. but below about 1850.degree. C. That is, the reaction is performed from left to right at higher than about 1,850.degree. C. to give the Mg a partial pressure of higher than 1 atm.
The reaction is performed right to left at lower than 1850.degree. C. In order to increase the yield of Mg, the reaction mixture of the mixed gas of Mg and CO is cooled to the temperature for inhibiting the reverse reaction. That is, it is necessary to rapidly cool the reaction mixture of the mixed gas below 400.degree. C. A coolant gas is usually used for the rapid cooling step. The coolant gas can be hydrogen, helium, nitrogen or a hydrocarbon gas such as methane.
Various attempts have been made to achieve a rapid cooling method and the apparatus therefor, such as a method of contacting the resulting mixed gas of Mg and CO with a water cooled plate so as to cool the mixed gas (U.S. Pat. No. 2,018,265), or a method of cooling the resulting mixed gas by ejecting a coolant gas from the center of a water cooling jacket formed at the outlet of the reactor as shown in FIG. 2 (U.S. Pat. No. 1,884,993).
However, the reverse reaction could not be satisfactorily prevented by these methods. In the latter method, a scale may be deposited around the outlet. These conventional methods have been unsatisfactory.